[*] Ensure failure on waiters if a task we're waiting on has already failed

Source/Async/WorkItem.cpp

@@ -45,6 +45,12 @@ namespace Aurora::Async
         {
             auto dependency = std::reinterpret_pointer_cast<WorkItem>(workItem);
             Threading::LockGuard<Threading::Primitives::SpinLock> l2(dependency->lock);
+
+            if (dependency->HasFailed())
+            {
+                Fail();
+            }
+
             dependency->waiters_.push_back(shared_from_this());
             waitOn_.push_back(workItem);
         }
@@ -77,6 +83,11 @@ namespace Aurora::Async
             dispatchPending_ = true;
         }
 
+        if (HasFailed())
+        {
+            return;
+        }
+
         for (auto itr = waitOn_.begin(); itr != waitOn_.end(); )
         {
             auto &waitable = *itr;
@@ -98,9 +109,9 @@ namespace Aurora::Async
         SendOff();
     }
 
-    
     void WorkItem::CancelAsync()
     {
+        Threading::LockGuard<Threading::Primitives::SpinLock> l(lock);
         Fail();
     }
 
@@ -130,8 +141,9 @@ namespace Aurora::Async
                 SetSchedTime(info.reschedMs);
             }
             WaitFor(info.waitFor);
-            // fall through
+
         }
+        [[fallthrough]];
         case IWorkItemHandler::EProcessNext::eRerun:
         {
             DispatchEx(false);